Porcelain-crown remover.



J. A. JOHNSON.

PORCELAIN CROWN REMOVER.

APPLICATION man FEB- 7, 1916.

1,177,706. Patented A r. 4, 1916.

ml: COLUMBIA PLANOGRAPH cm, WASHINGTON, D. c.

UNITED STATES PATENT OFFICE.-

J'OHN A. JOHNSON, OFCHICAGO, ILLINOIS, ASSIGNOR TO GOLDSMITH BROS.SMELTING 6'6 BEFINING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OFILLINOIS.

PORCELAIN-CROWN REMOVER.

Patented Apr. 4, 1916 Application filed February 7, 1916. Serial No.76,711.

To all whom it may concern:

Be it known that 1, JOHN A. JOHNSON, a citizen of the United States, anda resident of the city of Chicago, in the county of Cook, State ofIllinois, have invented certain new and useful Improvements inPorcelain-Crown Removers, of which the following is a specification.

This invention relates broadly to dental tools, and more particularly toan instrument for removing porcelain crowns.

The principal object of this invention is to provide an instrument forthe removal of a porcelain crown which may be desired to be removed fromthe tooth on which said crown has been permanently set.

A further. object of this invention is the production of an instrumentof the character specified wherein the porcelain'crown is removed bygradually forcing a wedge between the base of the crown and the tooth bymeans of relative movement between an abutment and a wedge member, bothof which are carried upon devices which extend to one side of the toothbeing operated upon.

A still further object of the present invention is the production of aporcelain crown remover wherein the operating jaws are carried upon bodymembers which extend substantially parallel and to one side of the zoneof operations of said jaws.

A still further object of the Present invention is the production of aporcelain crown remover comprising a pair of operating jaws, one ofwhich is wedge shaped, and wherein one of said jaws is carried upon abar adapted to extend over the crown being operated upon and atsubstantially right angles thereto.

7 A still further object of the present invention isthe provision in aporcelain crown 1 remover of a pair of jaws, one of which is wedgeshaped, and the jaw adapted to engage the lingual side of the toothbeing carried upon a member-extending at right an- I gles toland overthe top of the crown, and

the jaw engaging the labial side of the tooth' being carried upon amember having slidable engagement with the first mentioned member, andwherein a thumb screw is provided to cooperate with said members toclose said jaws.

Other and further objects of the present lnventlonwlll 1n part beobvious and will in part be pomtedxout hereinafter in the specificationby reference to the accompanying,

drawings wherein like parts are represented by like charactersthroughout the several vlews thereof.

Figure 1 is a perspective view illustrating construction to springtweezers with a pair of lnturned aws at their inner ends and providedwith a clamp screw whereby the jaws might be closed. With devices ofthis.

kind it is diflicult to insert the instrument in the patients mouth andproperly seat the jaws in position to displace the crown. One of thechief reasons for this difliculty is the fact that the body or mainportion of theiinstrument extends substantially in the direction of theaxis of the tooth and consequently in line with the correlated tooth inthe opposite jaw. Also in thistype of crown remover there ismore orlessdeviation of the operating jaws from their normal movement, due to thespring of the tweezer part of the body portion thereby to a certain extent destroying the positive action necessaryv to loosen the cementedcrown from its pos'ition on the tooth. Furthermore, removers of thischaracter lack a rigid hand hold one side of a rigid body portion whichex tends substantially parallel to the said j aws.

whereby the insertion and manipulation of the instrument in the patientsmouth is greatly facilitated. 'Furthermore', my invention includes aconstruction in which the jaws are constructed to be positively closedby endwise movements of rigid parts thus establishing a positiveforcible actlon of the jaws and overcoming the'difiiculties encountereddue to springing of parts under presbod-V porfion'so flp e instrumentmay b positively and" definitely operated.

Referring now more'particularly to the,

drawings the bar 1 is preferably square in cross-section. and, at itsinner end carries a right angle extension 2 on' the end of which isa jaw4 constructed to engage the lingual side of theotooth and whichpreferably extends substantially parallel to the bar. 1. The inner endof the'bar l is cylindrical and provided with screw threads 5 with whichis engaged the thumb nut 63* that bears against the outer end of thesquare sleeve or tubular member 7. This tubular-member 7 has an interiorcross section very slightly larger, than the cross-section of the bar 1so that th'ebar 1 snugly'fits within the'tubular member'for slidingengagement therewith and the outer end 8 of the tubular member Zisfilledto provide a shoulder'9 to com- I prise an abutment so that thespring 10 hear,-

ing against the shoulder 11 tends to substantially urge the bar inwardthus seatlng the thumb nut 6 firmly against the outer end of the tubularmember. The inner' end of the tubular membercarries an off-set extension12 on which ismounted a wedge shaped jaw 14 that is adapted to engagethe labialside of the tooth at the junction line between the tooth 15and the porcelain crown 16 thus wedging the crown loose from itsposition upon the tooth. In order to accommodate the crown pin 17 it isnecessary that one of the operating jaws be'bifurcated' and thereforeIhave illustrated the jaw 14 as'being provided with a slot 18. Sinceit isdesirable that the operating jaws be constructed so that one jaw willpass the other, I have illustrated the jaw 4;as being constructed topass over the jaw 14. To facilitate manipulation I have providedthetubular member 7 with finger; rings 19, rigidly secured thereto, so thatthese rings maybe used ashand holds so that the instrument may be givena rocking motion to make the action of the wedge elements mostefi'ective. 1

Realizing that it is possible to vary the physical embodiments of myinvention without departing from; the spirit thereof, I desire-that thespecific construction herein shown and described shall be understood asbeing illustrative and not in the limiting sense.

-;Having thus described my'invention what F1; In device of thefcharacterdescribed,

in combination, asquare bar provided with an off-set portion, a aw onthe end? of said off-set portion adapted to engage the lingual 7 sideof'the tooth, a tubular member having a squarecross-sectionopeningw-ith-in which said square bar is adapted tos'lide endwise,

an ofi-set member carried by said tubular" memberand provided on its endwith: a wedge shaped aw constructed to engage a tooth on the labial sideand to separate a cemented;porcelaincrown from the tooth to V which itis anchored, a screw threaded portion upon said squarebar,jand"extending b yond' the end of said tubular 'member, a"

thumb screw constructed to co-operatetwith said'threaded portion todrawsaid' bar outwardly relative to said tubular member thereby causingsaid jaws to positivelyxclose,

a coil spring within said tubular'member and bearing agalnst said squarebar tocon stantly exert pressure tending to opeii'isaid jaws and to seatsaid thumb screw against said tubular member, and a hand. hold formedupon saidtubular member: to enable saiddevice to, be manipulated.

' 2'. In a djvice, of the character described,

inrcombination, a square barprovided was tially parallel to the axis'ofsaid bar, alt ubus 1n member having the: opening itherein" square shapedin cross-section and within which said bar is adapted to slide, a jaw"mounted upon and off-set; from said-tubular member and being opposed tothe first'mentioned jaw, said jaw extending parallel/to the axis of thebar, and means togradually ii and positively close said jaws.

8. In a deviceof the character described,"

in combination, a rigid-bar provided with an off-set portioncarryinganioperatingjaw extending paralleltothe axis of the bar, V a;member secured-to and mounted to slide relatively to said bar, saidmember-carrying a aw adaptedtobeopposed to the firstmentioned aw andalso'extendingparallel tozthe axis ofthe bar, andmeansfor'graduallylandf positively moving said; bar and said mem barrelative each r o effecta Positive 7 ii In a device of thecharacter'described,

gradual and closing movement of 'saidjaws.

in combination, a pair of operating jaws, supporting members for saidjaws extending to one s'ideof theoperating zone ofsa i-d jaws'andparallel to the operative move ment' of-the jaws, and means cooperatingwith said supporting members 'to' gradually and positively close saidjaws.

5. In a porcelain crown.- removergincorm binatlon, a pair of jaws,lone-of which is we'dgeishaped, said wedge shaped jaw being providedwith a slotted opening, supporting 7 members for 'both of said jaws,said sup;

P embers extending to 1 one sid of the zone of operations of said jaws ad parallel to the movement of the jaws, a pair members carrying saidjaws, said jaws being of hand-holds secured to one of saidsupconstructed to permit one jaw to slide over porting members, and athumb screw for the other, a spring cooperating with the said 1positively closing said jaws. members and tending to open said jaws, and

5 6. In a porcelain crown remover, in coma thumb nut for positivelyclosing said jaws.

bination, a pair of opposed jaws, one of which is wedge shaped, a pairof sliding JOHN A. JOHNSON.

copies of this patent may be obtained for five cents each, by addressingthe "Commissioner of ratents, Washington, D. 0.

